Accurate multiple-input multiple-output fading channel simulator using a compact and high-throughput reconfigurable architecture

This article presents an ultra-compact and high-throughput reconfigurable fading channel simulator that supports a relatively large number of propagation paths. To closely reflect actual radio channels, the authors used a recently improved Rayleigh and Ricean fading channel model based on the sum-of-sinusoids technique. The improved model is optimised for hardware compactness. To achieve a fast fading variate generation rate with much less hardware and no significant loss in accuracy, the new scheme first generates fading samples at a lower rate using a time-multiplexed datapath that can be fit into a small fraction of a field-programmable gate array (FPGA). In the second step, the simulator uses a compact multiplication-free linear interpolator to produce the fading samples at the full symbol rate. Implementing a 64-path fading channel simulator on a Xilinx Virtex-4 XC4VLX200-11 FPGA requires only 13 044 (14%) of the configurable slices, 10 (2%) of the block memories and one (1%) of the dedicated DSP blocks, while generating 64 x 191 million complex-valued fading samples per second. The simulated paths can be readily combined to form high path count models for multiple-input multiple-output systems as well as frequency-selective channels.